Is the cure worse than the disease?

| April 16, 2021

Introducing the cane toad was to eliminate the cane beetle but the ‘cure’ became worse than the disease. Replacing leaded gasoline with unleaded petrol (ULP) was intended to benefit public health by reducing lead emissions from vehicles.

The World Health Organisation (WHO) has identified 10 chemicals of public health concern. Lead and benzene are two of those chemicals. Lead exposure can have serious consequences, especially for the health of children. As with lead, exposure to volatile organic compounds (VOCs) such as benzene may cause serious adverse health effects.

Benzene occurs naturally; it is found in crude oil and is emitted by volcanoes and forest fires. Regular ULP contains toluene, xylene and benzene to replace lead. Cars using ULP emit VOCs and very small (PM 2.5) particles. Benzene is known to cause severe illness in humans. It weakens the immune system and causes leukemia and other cancers. Anaemia, respiratory problems, menstrual issues and birth defects result from chronic exposure to benzine and other VOCs. Vehicles using premium ULP emit more benzene than those using regular unleaded.

Cigarette smoke contains VOCs and it is a health risk to smokers and anyone else exposed to it. The same goes for inhaling petrol vapours or exhaust fumes at the filling pump or anywhere vehicles are using ULP. The resulting health issues can be made worse by alcohol consumption.

The Australian government has been considering a ban on regular unleaded fuel for some time. Replacing regular ULP with ethanol blends would increase the price of petrol but public health would benefit from lower VOCs and PM 2.5 emissions.

EPA Victoria has issued a works approval for the construction of a secondary lead smelter to process used lead-acid batteries (ULAB) at Hazelwood North. Multiplying the maximum lead emission rate per minute as shown in the works approval, the annual lead emission is 54kg. However, that assumes the emissions would be the same at startup as in normal operations and that the plant would operate 24/7 without stopping for maintenance or other reasons.

For comparison, assuming most of the passenger vehicles in the Latrobe Region are run on ULP and average 13,000 km per annum, they would emit more than 12,000 kg of VOCs, much of it near ground level close to homes, schools, carparks and shops etc. And those automatic engine stop/restart systems are not only a nuisance, they’re a marketing gimmick used to fudge the fuel economy tests. worse still, cold start VOC emissions are up to 30 times more than for hot starts.

Lead is, and will remain a serious health risk that must be properly understood and managed. However, the risk of adverse outcomes is related to the level of exposure to any of the health hazards on the WHO list. With VOCs, including benzine, exposure is unavoidable and may be very acute and unpredictable.

It is surprising that so much attention has been given to lead but the health risk of VOCs is overlooked. Perhaps it is a case of familiarity breeding contempt. Or maybe it’s cheaper and more convenient to pretend that removing lead from petrol would allow us to keep motoring along on ULP like there’s no tomorrow.  But the ‘benzene toad’ might turn out to be as bad or worse than the ‘lead beetle’ it was meant to replace.